After the U-2 entered service in 1955 the CIA already planed its eventual replacement. The result was the Lockheed A-12 Blackbird and later the larger Lockheed SR-71. But Lockheed company were not the only company the CIA approached to developed the U-2 replacement. The second company Convair came up with an unusual and innovative proposal known as the Convair Fish and Superfish, but it never entered operational service.